Why Some Dishwashers Create Cloudy Glassware and How To Prevent It

Fred's Appliance
September 4, 2014


When you run a load of dishes through the dishwasher, you expect them to come out clean. After all, that’s the sole purpose of this convenient household appliance. Unfortunately, it’s not uncommon for dishwashers to leave a cloudy layer of residue on glassware and other dishes. So, what causes this phenomenon and how can you can prevent it?


There are two primary types of dishwasher-related cloudiness: film buildup and etching. The easiest way to determine which one is responsible for your hazy glassware is to rub the tip of a needle or pin against a glass to see how it reacts. If the glass scratches with a noticeable indention, it’s probably etching. If the surface remains intact, it’s probably a film buildup.


An alternative method involves placing a drop of vinegar on a cloudy glass. If the area is clean and clear when the vinegar dries, it’s film buildup.


Film Buildup


Film buildup is typically caused by water hardness (AKA heavy concentrations of minerals and chemicals in the water). When the water dries, it leaves behind a film consisting of compounds like calcium and magnesium. Detergent and water alone isn’t enough to remove this film; therefore, they must be re-washed by hand.


Food may also contribute to film buildup, especially when it contains protein. The compounds in the hard water connect with protein (eggs, meat, cheese, etc.), resulting in a thicker and more stubborn film.


If you believe film buildup is to blame for your cloudy glassware, try adding ¼ cup of white vinegar to your dishwasher. This will neutralize some of the hard water compounds, preventing them from sticking to your glassware.




Etching is defined as the erosion or pitting of glassware. Even if your glassware looks intact to the naked eye, it may possess numerous inclusions that are responsible for its hazy, cloudy appearance. Etching is caused from a combination of different elements, including the use of alkaline-based dishwashing detergents, high-temperature water, and the chemical makeup of the glassware.


There are several different things you can do to prevent the etching of glassware, one of which is to use less detergent. Most people blindly pour detergent into their dishwasher without measuring it beforehand. In doing so, there’s a greater risk of etching. Using just half of the recommended amount will clean your dishes just as well, and it may solve your cloudy glassware problem.

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